1. Field of the Invention
The present invention relates to a ceramic electronic component and a method of producing the same and, more particularly, to a ceramic electronic component having terminal electrodes formed on end faces of a ceramic member and a method of producing the same.
2. Description of the Related Art
Ceramic electronic components have a structure in which terminal electrodes are formed on a ceramic member comprising a conductor and a ceramic insulator, the terminal electrodes being connected to the conductor, respectively. Each terminal electrode comprises an external electrode formed by baking on an end-face of the ceramic member and a plating coat formed on the external electrode. As the plating coat, an Ni plating coat which provides a solder-proof property required for soldering is formed. Moreover, to enhance the soldering property, a plating coat made of Sn, Sn/Pb, or the like is formed. These plating coats are formed by so-called wet plating, that is, by electroplating the ceramic member in a plating solution.
The external electrodes, formed by baking, have fine voids. Furthermore, in the case in which internal electrodes are formed in the ceramic member, fine voids are present in the interface between the internal electrodes and the ceramic insulator. Therefore, when the ceramic member having the baked external electrodes is dipped into a plating solution, the plating solution intrudes into the voids of the ceramic member and the external electrodes, and remain there.
The plating solution generally contains different kinds of metal salts such as salts of Ni, Sn, Sn/Pb, and the like. These salts, when they remain in the ceramic member, behave as heterogeneous dielectrics. As a result, these salts in the presence of water migrate as ions, and cause the insulation resistance to decrease and so forth.
To prevent the plating solution from intruding as described above, a thermosetting resin such as phenols or the like is impregnated into the ceramic member, and is cured. Thereafter, the excess resin on the surface is eliminated therefrom by polishing or cleaned off by means of a solvent or the like. The voids of the ceramic member and the external electrodes are sealed with the resin, and plating coats are formed on the surfaces of the external electrodes by wet plating, as described above.
However, in the above-described method, it is needed to heat-set the resin and remove the excess heat-set resin on the surface of the ceramic member by polishing or cleaning. This is problematic in that the production process becomes complicated, is unsuitable for mass production, and becomes expensive.
Moreover, if the synthetic resin remains in the finished ceramic electronic component, the resin present in the voids may be dissolved or modified when the electronic part is mounted onto a printed circuit or is used in the atmosphere of high temperature and high humidity after it is mounted. Thus, the reliability of the electronic part may be deteriorated.